Blood Lead Levels Among Children
in High-Risk Areas -- California, 1987-1990

In the United States, elevated blood lead levels (BLLs) are a
major health risk for children; this risk is totally preventable
(1). To better characterize lead poisoning among children at high
risk for lead exposure in California, the California Department of
Health Services (CDHS) conducted lead-screening surveys that
measured lead levels in children's blood, household paint, and soil
in three selected high-risk areas in northern, southern, and
central California. This report summarizes the survey findings and
describes CDHS's efforts to reduce lead exposure among children in
California, especially among those in high-risk areas.

CDHS selected three areas for the surveys based on the
likelihood that old housing in these areas contained lead paint
(42%-72% of the housing in the survey areas was built before 1950):
Oakland in Alameda County (1987); Wilmington and Compton in Los
Angeles County (1988); and Sacramento in Sacramento County (1990).
In the Oakland and Sacramento survey areas, CDHS attempted to
enroll all households with children aged 12-59 months. In the two
communities in Los Angeles County, a systematic sample of every
fourth block was selected, and CDHS attempted to enroll all
households with children aged 12-59 months in those sample blocks.
The proportion of eligible households agreeing to participate in
each area included 358 (71%) of 506 in Oakland, 350 (56%) of 621 in
Wilmington/Compton, and 232 (47%) of 495 in Sacramento. Overall,
these households included 973 families with 1397 children in the
target age range (ages of children were equally distributed). *

In Oakland, initial blood lead testing was performed by
collecting capillary blood samples from the children. To reduce the
possibility of sample contamination caused by lead on children's
hands, their hands were vigorously washed before the capillary
sample was obtained; a confirmatory venous sample was obtained from
74% of the Oakland children with an initial capillary BLL greater
than or equal to 15 ug/dL. In Wilmington/Compton and Sacramento,
venous blood samples were collected from 96% of the participating
children; capillary samples were collected from the other 4% of
children surveyed.

In Oakland and Wilmington/Compton, household paint samples
were collected only when peeling or chipping paint was observed; in
Sacramento, paint samples were collected from surfaces regardless
of condition. At each household, soil samples of the top inch of
soil were collected from one to five locations (i.e., midsection of
front, back, and side yards; directly beneath a rain drain; and
near a building not attached to the house on the household
property); soil lead level was defined as the geometric mean of all
samples collected at the household. Paint lead levels reported were
the maximum level found at a home. Lead content in blood and
environmental samples was measured using graphite-furnace
atomic-absorption spectrophotometry.

In these three areas, 40%-84% of children were Hispanic and
members of families with reported annual family incomes of less
than $15,000. BLLs of greater than or equal to 10 ug/dL ** were
detected in 67% of children in Oakland, 32% in Wilmington/Compton,
and 14% in Sacramento. BLLs greater than or equal to 20 ug/dL ***
were detected in 5% of children in Oakland, 4% in
Wilmington/Compton, and 1% in Sacramento.

Geometric mean lead levels in household paint were highest in
Oakland and lowest in Wilmington/Compton (range for exterior paint:
3100-13,545 parts per million (ppm)) (Table 1). In all three areas,
exterior surfaces were substantially higher in paint lead levels
than were interior surfaces. However, lead levels for some interior
paint samples exceeded 5000 ppm (37% in Oakland, 25% in Sacramento,
and 13% in Wilmington/Compton). **** Soil lead levels were highest
in Oakland where 46% of household soil lead levels exceeded 1000
ppm.

Editorial Note

Editorial Note: Because recent research findings indicate that
adverse health effects may occur among children with BLLs greater
than or equal to 10 ug/dL, CDC guidelines recommend actions to
reduce lead exposure in communities where such levels are prevalent
(2). Before the CDHS assessment, the potential risk for childhood
lead poisoning had not been widely recognized in California or
other western states. However, the CDHS findings summarized in this
report indicate a high prevalence of elevated BLLs among children
in high-risk communities in California and are consistent with
reports elsewhere (4). Although many children participating in
these surveys had BLLs that exceeded the guidelines, the levels
were too low to cause overt symptoms; thus, in the absence of the
CDHS survey, the high prevalence of this problem in Oakland may not
have been recognized.

Lead-based paint, the most common source of high-dose lead
exposure for children (4), was present in a high proportion of the
dwellings surveyed by CDHS. In the western U.S. census region, an
estimated 80% of privately owned housing units built before 1980
contain some lead-based paint, and the prevalence and concentration
of lead in paint is proportionate to the age of the housing units
(5). In California, an estimated 560,000 children aged less than 6
years reside in housing units built before 1950 that probably
contain high levels of lead in paint (4).

In addition to lead-based paint, there are at least three
other important potential sources for lead exposure in California.
First, lead-contaminated soil was common in the communities
surveyed; in urban areas, such contamination may result from
deteriorating exterior lead-based paint and/or from emissions from
automobiles using leaded gasoline (2). Second, in California, seven
secondary lead smelters may contribute to contamination of nearby
soil. Third, in addition to environmental sources, the use of folk
medicines (6) and pottery containing lead is prevalent among some
minority groups and has caused severe cases of childhood lead
poisoning.

In January 1992, the use of leaded gasoline was banned by law
in California. In addition, CDHS is exploring other strategies to
remove lead from consumer products and to identify and remove lead
hazards from high-risk communities. The CDHS is implementing a
comprehensive lead-poisoning prevention program that includes
periodic blood lead testing for children aged less than 6 years;
case management by local health agencies; laboratory-based
reporting (2); and educational programs for local health
departments, health-care providers, and the public. During 1992,
CDHS has been preparing regulations for residential lead-paint
abatement. CDHS also is implementing strategies to reduce
occupational lead poisoning, prevent the use of lead-based folk
medicines, and eliminate other sources of lead exposure.

CDC. Preventing lead poisoning in young children: a statement by
the Centers for Disease Control--October 1991. Atlanta: US
Department of Health and Human Services, Public Health Service,
1991.

Office of Public and Indian Housing. Lead-based paint: interim
guidelines for hazard identification and abatement in public and
Indian housing. Washington, DC: US Department of Housing and Urban
Development, Office of Public and Indian Housing, 1990.

Agency for Toxic Substances and Disease Registry. The nature and
extent of lead poisoning in children in the United States: a report
to Congress. Atlanta: US Department of Health and Human Services,
Public Health Service, Agency for Toxic Substances and Disease
Registry, 1988.

US Department of Housing and Urban Development. Comprehensive
and workable plan for the abatement of lead-based paint in
privately owned housing: a report to Congress. Washington, DC: US
Department of Housing and Urban Development, Office of Policy
Development and Research, 1990.

In Los Angeles County, of 471 children surveyed, 272 were
excluded
because the blood collection tube lot used for their samples was
later found to be contaminated with lead; the remaining 199
children included in the study had household environmental lead
levels and demographic characteristics similar to those of the
excluded children. Paint and soil lead levels are presented for all
350 households.
** Levels at which adverse health effects in children have been
demonstrated (2).
*** Levels high enough to require medical evaluation according to
CDC guidelines (2).
**** According to guidelines established by the U.S. Department of
Housing and Urban Development (3), surfaces with paint lead levels
of greater than or equal to 5000 ppm should be abated during
comprehensive modernization activities.

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